Furnace.



Nrrno TATns WILLIAM B. ESTES, OF DANVILLE, ILLINOIS.

FURNACE.

SPECIFICATION forming part of Letters Patent No. 686,276, dated November 12, 1901.

Application filed June 29,

T0 @ZL whom it' may concern:

Be it known that I, WILLIAM B. ESTES, a citizen of the United States, residing at Danville, in .the county of Vermilion and State of Illinois, have invented certain new and useful Improvements in Furnaces; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the figures of reference marked thereon, which form a part of this specilication.

My invention relates to furnaces for boilers, and particularly to smoke-consuming furnaces. Its object is to provide means for returning the smoke and heavy gases from the smokebox into the tire-box for consumption.

A further object is to provide an artificial return-draft for the heavy smoke and gases and to mix steam or air, or both, therewith to assist in the combustion.

A further object is to separate the smoke and heavier products of combustion from the lighter products thereof and to return the former to the fire and allow the latter to pass out through the stack.

With these and other objects in view my invention is hereinafter described and is illustrated in the accompanying drawings, in which- Figure 1 is a longitudinal section, partly diagrammatic, of a furnace and return-flue boiler provided with my improvement. Fig. 2 is a diagrammatic front view of the boiler with the front wall removed. Fig. 3 is a detail sectional View of the air-valve in each return-pipe. y

In the said drawings the fire-box is indicated at 6, boiler-iiues at 7, smoke-box at 8, and stack at 9. In the smoke-box isan adjustable damper 10, consisting of a plate of the length and breadth of the interior of the. smoke-box and extending across the same horizontally. This damper is within the line of the iiues, so that part of the iiues open above the damper and part below the same. The purpose of the damper is to divide the products of combustion so that the smoke and heavier gases, which. naturally iiow through the lower flues of the boiler, may be collected and returned to the tire and the lighter products, flowing through the upper flues, allowed to pass out through the stack.

The fact that the smoke and heavier gases pass through the lower iues of a boiler is proved by the fact that the accumulation of soot in the lower tlues greatly exceeds that in the upper iiues and the further fact that by the use of my device the amount of smoke discharged and coal consumed is greatly reduced.

When the fire is starting or steam being raised, the damper maybe raised to allow all the iiues to communicate directly with the stack.

Directly below the .damper in the smokebox are hoods 11, preferably two in number, and the mouths thereof are oppositely disposed tothe rows of iiues below the damper and are adapted to collect the smoke and gases which pass through said lines. Connected to the hoods are pipes 12, which extend outwardly and forwardly beyond the front wall of the furnace and are thence bent downwardly and inwardly through the said wall and into the fire-box. The transverse area'of these pipes is substantially equal to the transverse area of the fines below the damper, so that the draft is not obstructed or decreased, as in the case where the return-pipe is made of small capacity. The pipes are preferably two in number, one on each side, so that the returned products are distributed equally 'to each side of the fire-box.

The steam-space of the boiler is tapped by a steam-pipe 13, which enters the pipe 12 and is adapted to discharge therein a steam-jet in the direction of the flow of gases through the pipe. The discharge-nozzle 14C of the steampipe is near the exit 15 of the return-pipe, and thereby an exhaust-draft is created which causes the products entering the mouth 11 of the pipe to be carried through the pipe and into the fire-box mixed with the steam. By placing the steam-jets near the exits of the pipes the use of the desirable pipes of large capacity, as hereinbefore referred to, is permitted, giving a much better result than if the steam-j ets discharged in the return-pipes near the entrance thereof. Furthermore, each return-pipe 12 is provided with an air- IOD inlet valve 16, through which air may be admitted into the pipes and be mixed with the smoke and other products before they are discharged into the re-box. By thus mixing heated gases, carbonaceous substances, air, and steam a highly-combustible mixture is formed, and a fire is produced which consumes practically all of the smoke and combustible gases and results in a large saving` of fuel, as well as the prevention of an undesirable discharge of smoke. The inlet-Valve 16 also serves to admit air to support the ire when the grates are clinkered badly, and sufficient air to produce proper combustion is not admitted through them.

The supply of steam is controlled by the valve 13a in the steam-pipe and the supply of air by the proper adjustment of the valve 16. This valve may be of any suitable form. I have illustrated a simple slide adapted to cover or uncover openings in the pipe.

My invention may be applied to any ordinary return-flue boiler Without alteration of the structure thereof. The parts are cheap and simple and not liable to get out of order.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

In combination, a furnace, a boiler, a damper adapted to separate the combustion products passed through the lower boiler-dues from those passed through the upper boilerflues, hooded return pipes, the mouths of which are arranged side by side, which pipes are substantially equal in area to the lower boiler-dues, leading downwardly and laterally therefrom to each side of the furnace and adapted to equally distribute said products to each side of the furnace, pipes to discharge steam-jets'int-o the return-pipes near the exits thereof, and an independently-operative air-inlet valve in each of the returnpipes.

In testimony whereof I affix my signature in presence of two witnesses.

WILLIAM B. ESTES.

Witnesses:

C. M. SWALLow, MABEL R. SwALLoW. 

